For the last decade, the speed of modem digital electronics has significantly increased. To use SONET as an example, its bit rate quadrupled several times from OC-12 (622 Mbps) to OC-192 (10 Gbps). Currently, OC-768 (40 Gbps) is on the horizon. To use Intel's Pentium family microprocessors as another example, their clock speed was 60 MHz and 66 MHz in 1993 for the original Pentium processors, and it is now 1.4 GHz and 1.5 GHz for the Pentium 4 processors. For such high-speed applications, signal integrity has become an increasingly important issue, among which, jitter remains to be a critical performance criteria.